The nature of the mechanism of insulin control of rat liver glycogen synthase activation will be determined. The effect of alloxan diabetes in rats on the properties of liver glycogen synthase will be evaluated by kinetic and physical means as a measure of the diabetes-induced alteration of the synthase as well as the enzyme capability for regulation by an interconversion system. Insulin control of the synthase activity will be evaluated in terms of a hormone effect on the synthase and its activating enzyme and should provide evidence of the molecular pathophysiology of diabetes.